Picture transmission



May 10, 1932. E. F. w. ALEXANDERSON PICTURE TRANSMISS'IQN Filed June 5, 1930 Inventor:

ErnstFTwAlexar-mderson HisAttorneg.

Patented May 10, 1932 UNITED "STATES PATENT; OFFICE;

ERNST r. w. ALEXANDERSON, or SCHENECTADY, NEW Yonx, AssIGNon'ro GENERAL ELECTRIC COMPANY, A CORPORATION on NEW YORK PICTURE TRANSMISSION Application filed June 5, 1930. Serial No. 459,366.

My invention relates to the transmission of pictures, and it has for its object the provision of improved apparatus for this pur- I pose which withoutbeing operated at higher mechanical speeds permits of higher picture transmission speeds than heretofore.

In my copending application Serial No.

ratus, the sending part of which scans the picture to be sent a single line at a time, the s ccessive impulses produced in accordance with the shades of the unitareas of the picture in V ceiver. ber is exposed one line at a time to light whlch such line being transmitted by radio-to the re- At the latter a light sensitive memis modulated in accordance with the received signal.

In accordance w1th my present mvention which is an improvement over the abovementioned invention, the'picture to be sent.

is scanned simultaneously in a plurality of scanning lines, impulses corresponding with the shades of the unit areas in the plurality of scanning lines are transmitted simultane ously and at the receiver the light sensitive member is exposed simultaneously in a plurality of parallel lines. o My invention willbe better understood from the following description taken incon-v neotion with the accompanying drawings, and its scope will be pointed out in the appended claims. v V

In the drawings, Figs. 1 and 2 represent those portions of the apparatus involving my invention respectively for sending and receiving a transmitted picture.

Referring first to Fig. 1, I

necessarily a complete cylinder, for the paper or other member 2 bearin the icture to bev c transmitted which in pagsing ig spectlvely the photo-electric cells 22 and 23. support is bent to a form which preferably' "is approximately semi-cylindrical. Asmy invention is equally applicable where the picture is bent through various smaller arcs, I intend that the term semi-cylindrical asused in the claims shall apply to all such cases. Likewise the term cylindrical. as applied have shown at 1 Y a support of cylindrical form, although not to the support does not necessarily mean that the support must be in the formof a complete cylinder. .In the form illustrated the paper 2 extends through an arc of a little less than 180. 'Anysuitable means may be provided for drawingthe paper inan axial direction through the support at. a uniform, slow speed. In the, support 1 is the narrow window 3 through which the picture is scanned. Arranged axially of the suport 1 is the shaft 4, one end'of which is hollow and ,attheother end of which is supported the condensing lens ;5 whichserves tofocus on thepicture at the properpoint light from the lamp 6. Ex-

fending radially from the shaft 4 is the'lens member 8, the outer end of which is arranged to pass longitudinally over the window3 and at the inner end of which is the prism9. The shaft is shown adapted to be rotated by motor connected therewith by the worm 11 and the worm wheel-12, which is fixed to the shaft. At theopposite endof the shaft 4 is the diaphragm 14 having therein two small holes 15 on which the lens member 8 in conjunction with the prism 9 focuses'images respectively of unitareas of the picture lying in two adjacent scanning-lines. In front of the diaphragm 14 I'have shown the chopper 17, which is 'providedwith teeth of sufficient length to interrupt the lightrays passing through both holes 15. The chopper is shown drivenby a separate electric motor 18, the speed'of which governs thefrequency of theaudio carrier wave which by way of example may be 3000 cycles per second. In front of thediaphragm 14 and beyond the chopper are the two similar spherical lenses 20 and 21 each of which, hasa segment removed therefrom with the remaining portions juxtaposedx Ator approximately at the focal pointsof lenses20 and 21 are re- The output circuits of these cells are shown connected respectively with the radio transmitters 24am 25, each provided with "an, antenna and adapted to transmit on two radio waves which differ from each other by a relaquency of 17,300 K. C. and the transmitter may transmit at a frequency of 17,310 K. C.

As the chopper and scanning device rotate, the light rays from two adjacent scanning lines pass through the two openings 15, are interrupted bythe chopper 17 and thereafter I apparatus shown in Fig. 2, I have shown a pass through the respective'lenses 20 and 21 into the respective cells 22 and 23. As the shaft rays always reach the cells.

Referring now to the receiving part of the support 30, which is similar to the support 1 'of't'he sending apparatus through whicha light sensitive member '31 is adapted to be drawn with a uniform slow movement by any suitable means not shown. Member 31 like the picture 2 is bent preferably to form approximately a semi-cylinder but if desired 'may'form a smaller are, the term semi-cyliir' drical as used in the-claims being intended port 1 isprovided with thenarrow window 32.

to apply in such cases. Support 30 like sup- Similar also to the construction shown in Fig.

1, is the hollow shaft 33 having the worm gear v34: thereon meshing with the worm 35 driven by "the motor 36, which by suitable means is caused to rotate at a speed corresponding with the speed of the motor'10 of the sending apparatus. "Shaft 33 also supports the lens member 38 and prism 39 as in the previously described construction and at the opposite end,'the shaft is provided with the diaphragm 40 having therein two holes 41. In front of the diaphragm-are the two spherical lensesl2 and 43, which as before have segments removed therefrom with the remaining portions in juxtaposedrelation. Atthe fo cal points of lenses 42 and 43 "are arranged respectively the discharge 'lamps'fit and 45,

which preferably are lamps having a concentrated source of light which is susceptible to high; frequency modulation. I have shown the'lamps-aa and 15 connected to radio receivers 46 and 47 respectively, each having an antenna and tuned to receive the signals trans lamps-a4 and 4-5.. 'Since these lamps are ar-- mitted respectively from the transmitters 24 a d 25. v 1

In operation the separate signals or impulses being received by the two receivers 16 and 47, cause the operation of, the respective ranged at the focal points of the lenses 42 and 43, the ligh-t rays from each lamp i1- luminate the entire diaphragm .40. The two openings 41 in the diaphragm 40 now become in effect two light'sources which by means of the ,lens member '38 and the prism 39' are focused as separate adjacent spots on the light sensitive member 31. As the shaft rotates the two spots trace two adjacent parallel lines on the light sensitive member, each spot being varied independently of the other in accordance with the signals received by the respective receivers 46 and 47.

While I have shown and described apparatus for scanningthe picture simultaneously in two adjacent lines, and likewise in reforming the picture by exposing it simultaneously in two lines, it will be understood that my invention is not limited to such but applies also to apparatus by which the picture may be scanned simultaneously in a greater number of lines, andlikewise reformed simultaneously in a like greater number of lines. I have chosenthe particular embodiment described above as illustrative of my invention and it will be apparent that various modifications may be made without departing from the spirit and scope of my invention, which modifications I aim to cover by the appended claims. 7 I

What I claim as new and desire to secure by Letters Patent of the United States is 1. Picture transmitting apparatus comprising a cylindrical member adapted to sup- 7 port a picture to be sent, a scannlng lens member-rotatably supported coaxially'with said cylindrical member, a plurality of fixed light responsive devices, and means cooperating with saidlen'smember for directing simultaneously'towarda plurality of fixed: points occupied by said devices'the light rays respectively from adjacent areas in separate scanning lines ofthe picture.

2. Picture transmitting apparatus comprising a cylindrical member adapted to'support a picture to be sent, a scanning lens memberrotatably supported coaxiall-y with said cylindrical member, a plurality of photoelectric devices, and aplurality of'light refracting'members between the lens member and said devices arranged to direct simultaneously toward the fixed points occupied by the respective devices light rays from separate scanning lines of a picture of approximately semi-cylindrical form.

3." Picture transmitting apparatus comprising a cylindrical member adaptedto supporta picture to be sent, a scanning lens member rotatablysupported coaxially with said cylindrical member, a plurality of fixed photoelectric cells, and a plurality of fixed light r'efracting members between the lens member and said cells arranged to direct simultaneously into the cells light rays respectively from adjacent areas in separate scan ning lines of the picture.

4; Picture transmitting apparatus comprising a cylindrical member adapted to support a picture to be sent, a scanning lens member rotatably supported coaxially with said cylindrical member, a plurality of fixed photoelectric cells, separate transmitting apparatus connected with each cell, a plurality ill) of fixed light retracting members associated therewith and arranged to direct into the cells light received respectively from each of a plurality of separate scanning lines of a picture of approximatelyv semicylindrical form.

5. Picture transmitting apparatus comprising a cylindrical member adapted to support a picture to be sent, a hollow rotatable shaft having a scanning lens member and a diaphragm provided with a plurality of light openings therein, a plurality of fixed photoelectric cells, a light retracting member associated with each of said cells and a single light chopper for light passing both of said openings, the arrangement being such that the cells simultaneously receive light respectively from separate scanning lines of the picture.

6. Picture transmitting apparatus comprising a cylindrical member adapted to support a picture to be sent, a hollow rotatable shaft having a scanning lens member and a diaphragm provided with a plurality of light openings therein, a plurality of fixed photoelectric cells, and a plurality of fixed lenses arranged in cooperation with said scanning lens member to project simultaneously into the respective cells light from each of a plurality of separate scanning lines of the picture.

7 Picture transmitting apparatus comprising a cylindrical member adapted to support a light sensitive member, a plurality of fixed sources of modulated light and means including a lens member rotatable concentrically of said cylindrical member for project ing' light simultaneously from each of said sources in the same direction in parallel paths on the light sensitive member.

8. Picture transmitting apparatus comprising a cylindrical member adapted to support a light sensitive member, a plurality of fixed sources of light, means for separatelymodulating the light from each source, a lens member rotatable concentrically of said cylindrical member, and fixed means cooperating said lens member for causing the light from said sources simultaneously to expose the light sensitive member of semi-cylindrical form respectively in a plurality of parallel paths.

9. Picture transmitting apparatus comprising a cylindrical member adapted to support a light sensitive member, a plurality of fixed sources of light, means for separately modulating the light from each source, a lens member rotatable concentrically of said cylindrical member, a plurality of fixed lenses at the focal point of each of which is arranged one of said light sources, and a diaphragm rotatable with said lens member and arranged to be illuminated by all of said sources, said diaphragm having a plurality of openings therein arranged to be simultaneously imaged by the lens member on the light sensitive member.

10. Picture transmitting apparatus comprising a cylindrical member adapted to support a pictureto be transmitted, means rotatable coaxially with said member for scanning an approximate semi-cylindrical picture simultaneously in a plurality of parallel lines, a plurality of fixed light responsive devices and means in cooperation with said scanning means for directing to the several light responsive devices respectively the light from the several parallel scanning lines.

11. Picture transmitting apparatus coniprising a cylindrical member adapted to support a light sensitive sheet, means rotatable coaxially with said member for scanning an approximately semi-cylindrical sheet simultaneously in a plurality of parallel lines, a

plurality of fixed sources of modulated light,

and means in cooperation with the scanning 

